White or wholegrain bread?

I’ve always been told and gone with the fact that wholegrain has to be better than white bread. For those of us interested in health, the results of a recent new study comparing the health effects of white bread versus wholegrain sourdough bread are very interesting indeed.

The study compared the effects of consuming white bread for one week, followed after a break by consuming wholegrain sourdough for one week, or vice versa. Those taking part in the study, were asked to have the equivalent of 3-4 slices of bread for breakfast and then to have additional bread throughout the day and were told not to consume any other wheat-based products, including pasta or other breads that were not included in the study.

The researchers were expecting to see differences in the rise in blood sugar after the participants consumed the white bread versus the wholegrain sourdough bread and they also looked to see if people’s gut flora changed. However, they didn’t find any differences in either case when comparing consumption of white and wholegrain breads.

What they found was that people’s individual responses to bread, in terms of glycaemic response, varied much more than they expected and in some cases, were opposite to what they would have predicted from the Glycaemic Index values of the bread, i.e. some people had a higher glycaemic response to the wholegrain bread, than the white bread.

The researchers also looked at whether these differences could be linked to differences in gut flora and found that there did appear to be a relationship between the two and suggest that in future this should be taken into account when giving dietary advice.

This was a very small study of short duration and so the findings need to be interpreted with caution. The study also didn’t include any in-depth measures of other dietary intakes and so it’s not possible to look at whether other dietary factors could have affected the results in the longer term. Also, those taking part ate a fairly large quantity of bread, which may not be a realistic dietary pattern.

Most people have no way of knowing the composition of their gut flora and so wouldn’t be able to make food choices based on this, therefore choosing wholegrain bread and other wholegrain foods still remains very important as our fibre intakes generally remain well below the recommendation of 30g per day.